Abstract

We have investigated the reduction of unwanted interfacial SiO2 layer at HfO2/Si interface brought about by the deposition of thin Hf metalbuffer layer on Si substrate prior to the deposition of HfO2thin films for possible direct contact between HfO2thin film and Si substrate, necessary for the future generation devices based on high-κ HfO2 gate dielectrics. Reactive rf magnetron sputtering system along with the attached in-situspectroscopic ellipsometry (SE) was used to predeposit Hf metalbuffer layer as well as to grow HfO2thin films and also to undertake the in-situ characterization of the high-κ HfO2thin filmsdeposited on n-type 〈100〉 crystalline silicon substrate. The formation of the unwanted interfacial SiO2 layer and its reduction due to the predeposited Hf metalbuffer layer as well as the depth profiling and also structure of HfO2thin films were investigated by in-situ SE, Fourier Transform Infrared spectroscopy, and Grazing Incidence X-ray Diffraction. The study demonstrates that the predeposited Hf metalbuffer layer has played a crucial role in eliminating the formation of unwanted interfacial layer and that the deposited high-κ HfO2thin films are crystalline although they were deposited at room temperature.

This research was supported mainly by The Scientific and Technological Research Council of Turkey (TUBITAK) with Project Nos. 107T117, 113F349, and partially by Izmir Institute of Technology with research Project No. 2008 IYTE 37. We would like to thank “Applied Quantum Research Center (UKAM)” located at the Physics Department of IZTECH.